Method for preparing butanediol by carrying out two-stage catalytic hydrogenation on butynediol

Abstract

The invention relates to a method for preparing butanediol by carrying out two-stage bed catalytic hydrogenation on butynediol. Aiming at the requirements on the suitability for a reaction system which contains water or fluctuating water content in a process for preparing the butanediol by carrying out two-step hydrogenation on the butynediol, and the inhibition on the generation of carbon deposit, the inventor proposes that: a hydrogenation catalyst A and a hydrogenation catalyst B in a two-stage bed respectively contains a carrier, a metal active component and silane groups, further, the silane groups are grafted through a silylanizing treatment, wherein the content of the silane groups in the total weight of the hydrogenation catalysts is 0.1-12 wt%. Compared with the prior art, under the premise of ensuring that the hydrogenation catalysts have better activity and better selectivity, the method provided by the invention has obvious raw material suitability, and the presence of water hardly influences on the catalytic performance of the hydrogenation catalysts; and meanwhile, the generation of the carbon deposit on the surfaces of the catalysts can be obviously inhibited, and the service life of the catalysts is prolonged, so that the hydrogenation reaction system can have a longer stable running cycle.

Description

technical field [0001] The invention relates to a hydrogenation method, more specifically, the invention relates to a method for preparing butanediol by two-stage catalytic hydrogenation of butynediol. Background technique [0002] 1,4-Butanediol (BDO) is a widely used chemical raw material, mainly used in the production of polybutylene terephthalate (PBT), tetrahydrofuran (THF), γ-butyrolactone (GBL), poly Tetramethylene ether glycol (PTMEG), N-methylpyrrolidone (NMP), polyurethane thermoplastic elastomers and fibers, etc. In addition, BDO can also be used as a solvent, wetting agent, plasticizer and chain extender and crosslinking agent in polyurethane synthesis. [0003] The production process of 1,4-butanediol mainly includes Reppe method, butadiene acetoxylation method, propylene oxide method and maleic anhydride method, etc. Among them, the method of hydrogenating butynediol to butanediol belongs to one part of the Reppe method: the acetylene diol generated by the re...

AI Technical Summary

Problems solved by technology

Co-precipitation method to prepare catalysts has the problems of cumbersome operation, long process and difficult control of preparation conditions, which easily leads to unstable quality of catalyst products

At the same time, a large amount of wastewater generated during the precipitation and washing process contains residual metal ions, resulting in the loss of effective components and causing environmental pollution

[0006] Chinese patent CN1172792A provides a two-step hydrogenation of 1,4-butynediol to prepare 1,4-butanediol. It can only be understood from the examples that the two-stage fixed-bed hydrogenation catalyst is a diatomaceous earth It is a catalyst containing 56.1wt% nickel and a small amount of copper as a carrier, and the preparation method of the catalyst is not disclosed in the patent

This makes the catalyst in industrial operation, the reaction activity is reduced, and the service life is reduced

It should be pointed out that in the actual operation of the industry, the change of water content in the reactor is often irregular, and the sudden change will cause large fluctuations in the selective hydrogenation effect of phenylacetylene, resulting in the instability of the catalyst operation.

In addition, since the two-step hydrogenation of butynediol to butanediol reacts at high temperature and high pressure, a large number of by-products produced are likely to produce colloid and other coking precursors, which cause carbon deposition on the catalyst and affect the hydrogenation performance of the catalyst.

[0010] However, the existing two-step hydrogenation process of butynediol to butanediol fails to consider the influence of water and surface area carbon in the reaction system on the activity and stability of the hydrogenation catalyst.

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